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Roadrunner
10

Roadrunner 10

This is probably some sort of bivalve shell, yet the ends of it seem different than what I've seen before. Maybe I'm imagining that, as shells do seem to spread as they go toward the ends. This rock is sedimentary, is about 15-20 pounds and has another shell trace in it that I'll post below.

Same one;

Other side;

Same "other side" trace.

Edited March 13, 2013 by Roadrunner

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Roadrunner
10

Roadrunner 10

Finally, I always find a LOT of crinoids as you can see on this sedimentary rock. However, I keep finding this oval-shaped traces that I can't identify. The 1st and 2nd pictures shows the crinoids, and the second on the same rock shows the oval shape. Can anyone identify the oval-shaped trace?

....and the oval shape with a folded-type shape to the left of it, that I also keep finding.

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Roadrunner
10

Roadrunner 10

I think most of it is Pennsylvanian Era, but the area is very geologically complex (slightly north of Albuquerque, NM and on the northern foothills of the Sandia Mountains). I'm still trying to positively identify a heavy boulder that I found last year and have in another thread.

Terry Dactyll
191

Terry Dactyll 191

Hi Roadrunner.... Some nice material there.... I think your right with shell imprints in some of the pieces and the last one I think is a worn gastropod.... I think you have posted this one previously I remember the dogs paw pointing it out...

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Roadrunner
10

Roadrunner 10

Hi Roadrunner.... Some nice material there.... I think your right with shell imprints in some of the pieces and the last one I think is a worn gastropod.... I think you have posted this one previously I remember the dogs paw pointing it out...

PS.... The nautilus.... It certainly looks nautilus shaped and I can see why you would think this but I'm not convinced for sure it is one...

Thank you, Terry. I couldn't remember if I'd put the one with the dog paw in before....

I guess that I have to look up the difference between an ammonite, gastropod, nautillus. I'm a bit confused about that.

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FossilDAWG 4,107

FossilDAWG 4,107

The photos by the cell phone, labeled "no clue", are solitary rugose corals. The "nautilus" (also called an ammonite by some) is certainly a section through a snail (gastropod), as there is no evidence of internal division into chambers (called "camerae"). Also the "nautilus" in post #10 is a chert (flint) nodule.

Overall, with the corals, crinoid stems, gastropods, and chert in massive limestone, I suspect you are looking at the Lake Valley Formation, which is Mississippian in age. Some parts of the formation, such as the Nunn Member, are more shaley and have lots of fossils, including crinoid calicies, that weather out completely. There is also Permian limestone in the area, but the fossils are different, mainly fusilinids.

I don't see any fossils in the first photo, I think that is probably a cool mineral specimen.

You live in an area with a lot of diversity in therms of ages and types of fossils to be found, once you start to learn the geology. I believe you are close to some Cambrian, and lots of Ordovician, Devonian, Mississippian, Pennsylvanian, Permian, and Cretaceous fossils. If you have not yet seen the book "Paleontology of New Mexico" by Barry Kues, I recommend picking up a copy or seeing if your library has one. You'll probably want a copy of your own though once you have a look at it.

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Roadrunner
10

Roadrunner 10

The photos by the cell phone, labeled "no clue", are solitary rugose corals. The "nautilus" (also called an ammonite by some) is certainly a section through a snail (gastropod), as there is no evidence of internal division into chambers (called "camerae"). Also the "nautilus" in post #10 is a chert (flint) nodule.

Overall, with the corals, crinoid stems, gastropods, and chert in massive limestone, I suspect you are looking at the Lake Valley Formation, which is Mississippian in age. Some parts of the formation, such as the Nunn Member, are more shaley and have lots of fossils, including crinoid calicies, that weather out completely. There is also Permian limestone in the area, but the fossils are different, mainly fusilinids.

I don't see any fossils in the first photo, I think that is probably a cool mineral specimen.

You live in an area with a lot of diversity in therms of ages and types of fossils to be found, once you start to learn the geology. I believe you are close to some Cambrian, and lots of Ordovician, Devonian, Mississippian, Pennsylvanian, Permian, and Cretaceous fossils. If you have not yet seen the book "Paleontology of New Mexico" by Barry Kues, I recommend picking up a copy or seeing if your library has one. You'll probably want a copy of your own though once you have a look at it.

Don

Thank you. We do have that book and we've studied it. The problem - and the blessing, is the specific area where we live has one of the most diverse cross-sections of exposed ages that you can find in the State. A geologist at a local university told me she thought the area was Pennsylvanian - though she also thought the boulder I've been researching was caused from erosion. We are sure that boulder displays mostly organic features. She also thought there was no chert in our area, and yet she agreed that what I discreetly brought in was chert. So she modified what she stated to say there were "chert nodules" in the area.

It certainly isn't a simple area. And yet, that makes it all the more interesting!

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Roadrunner
10

Roadrunner 10

I'm guessing the main little dude is some kind of rugose coral - along with some scattered crinoids, etc., but I really have no idea as I can't find anything with that shape, and the center piece with lines radiating around it. It is a little more than an inch long.